Block heat exchanger, method for implementing same and heat exchange block belonging to such an exchanger

ABSTRACT

An exchanger having an enclosure with a bottom ( 5 ), a cover ( 4 ) and a peripheral casing ( 6 ), at least one block ( 1 - 3 ) disposed between the bottom and the cover, each block comprising a body, longitudinal channels ( 10 ) and transverse channels ( 12 ). At least one of the interfaces ( 112, 114, 123, 135 ) between two opposite front faces belonging to the cover and to the block adjacent thereto, to the bottom and to the block adjacent thereto, or optionally to two contiguous blocks, a so-called radially inner peripheral seal (J 1 , J′ 1 ) is provided, extending radially outside the area ( 14 ) of the openings of the longitudinal channels, and a so-called radially outer peripheral seal (J 2 , J′ 2 ) defining, with the inner peripheral seal and the opposite front faces, an annular space (E, E′) for containing a possible leak of one or the other fluid.

TECHNICAL FIELD OF THE INVENTION

The invention relates to the technical field of block heat exchangers. It relates more particularly to such a block heat exchanger, which is equipped with means for identifying a potential leak of one of the fluids circulating in this exchanger.

PRIOR ART

Numerous types of heat exchangers are known, of which mention shall be made inter alia of plate, tube or fin exchangers. The invention relates more particularly to a block type heat exchanger, comprising an enclosure wherein at least one heat exchange block is housed. Usually, this enclosure receives a plurality of these blocks, which are stacked on top on one another.

Each block is made of a thermally conductive material, such as graphite optionally associated with additives, for example of the polymer type. This block, which may be parallelepipedic or cylindrical, is hollowed with two series of channels extending perpendicularly to one another. These channels are intended for the circulation of two fluids, with a view to the mutual heat exchange thereof. Typically, the first fluid is for example an acid, while the second fluid is a heat transfer fluid, particularly water.

There are two main designs, for the embodiment of the above heat exchange blocks. According to a first design, the first channels are longitudinal and open onto the front faces of the body, while the second channels are transverse and open onto the opposite transverse faces of the body. In an alternative design, both the first and second channels are longitudinal and open onto the front faces of the body.

The opposite front faces, belonging to two contiguous stacked blocks, are mutually supporting. Moreover, the end blocks are respectively placed against the bottom and the cover of this enclosure. The latter is finally equipped with different tubes, for supplying the fluids in the two series of channels, as well as the discharge thereof from these channels. Block heat exchangers are for example known from EP-A-0 196 548, or from WO-A-2006/081965.

It is understood that the technical problem of sealing takes on particular importance in this type of exchanger. Indeed, if a leak of one of the two fluids circulating in the channels occurs, there is a risk of mixing between these fluids. This leak induces at the very least an economic loss since the fluids placed in mutual contact are no longer usable, or even a material and human risk if the mixture of the fluids is hazardous, particularly if it is explosive.

Various solutions have already been proposed, with the aim of monitoring satisfactory sealing between the fluids circulating in heat exchangers. Mention shall particularly be made of the following documents: WO-A-2005/119197, DE-A-195 01 467 or DE-A-433 13 14. These different arrangements are not however applicable to block exchangers, at least directly.

Finally, from FR 1 421 491 and FR 1 465 780, a heat exchanger formed from at least two blocks is known, each whereof is hollowed with different channels. These channels are distributed along concentric lines, two adjacent lines being separated by a respective seal. Such an arrangement is not however totally satisfactory, with regard to sealing issues. Indeed, it is not suitable for containing a potential leak, or signaling simply and quickly the occurrence of such a leak to an operator.

That being said, one aim of the present invention is that of providing a block heat exchanger which exhibits enhanced sealing relative to exchangers of the same type, known from the prior art.

A further aim of the present invention is that of providing such a heat exchanger, which enables effective monitoring of the sealing between the two fluids circulating in the channels of this exchanger.

A further aim of the present invention is that of providing such a heat exchanger, which has a relatively simple structure and which can be manufactured without any particular risk of mechanical rupture, particularly with respect to the channels hollowed in the blocks belonging to this exchanger.

OBJECTS OF THE INVENTION

One object of the present invention is a heat exchanger comprising

-   -   an enclosure having a bottom, a cover and a peripheral casing,     -   at least one block arranged between the bottom and the cover,         each block comprising a body, first so-called longitudinal         channels, formed in this body along a longitudinal direction of         the block, which open onto two opposite front faces of the body,

the exchanger further comprising first inlet means of a first fluid into the first channels, second inlet means of the second fluid into the second channels, first outlet means of the first fluid from the first channels, second outlet means of the second fluid from the second channels, sealing means between the first and second fluids,

said exchanger being characterized in that the sealing means comprise, on at least one interface of the interfaces between two opposite front faces belonging to the cover and to the block adjacent thereto, to the bottom and to the block adjacent thereto, optionally to two contiguous blocks, at least one so-called radially inner peripheral seal, each inner seal extending radially outside the area of the openings of at least a portion of the longitudinal channels, and a so-called radially outer peripheral seal defining, with the inner peripheral seal(s) and the opposite front faces, a space for containing a possible leak of one or the other fluid.

According to further features of the exchanger according to the invention:

-   -   the second channels are transverse and a single radially inner         seal is provided, extending radially outside the area of the         openings of the longitudinal channels, the containment space         being annular in shape;     -   the second channels are also longitudinal and at least one first         radially inner seal is provided, each first inner seal extending         outside the area of the openings of at least a portion of the         first longitudinal channels, as well at least one second         radially inner seal, each second inner seal extending outside         the area of the openings of at least a portion of the second         longitudinal channels;     -   the first and second longitudinal channels are arranged in a         succession of alternating rows, the area of the openings of each         row being surrounded by a respective radially inner seal;     -   the sealing means comprise said at least one inner peripheral         seal and said outer peripheral seal, at all of the interfaces         between two contiguous blocks;     -   the sealing means comprise said at least one inner peripheral         seal and said outer peripheral seal, at all of said interfaces;     -   the exchanger further comprises detection means suitable for         detecting the presence of at least one of the first and the         second fluid, inside at least one annular containment space;     -   the exchanger further comprises an alarm suitable for being         activated by detection means;     -   the exchanger further comprises discharge means suitable for         discharging outside the enclosure said potential leak of one or         the other fluid, contained in at least one annular space;     -   the discharge means are placed in communication by the fluid         with the detection means;     -   the detection means are at a distance from the enclosure and a         connection pipe suitable for connecting these detection means         and the opening of the discharge means is provided;     -   the discharge means comprise at least one discharge conduit,         each discharge conduit being provided in a respective block and         connecting two adjacent containment spaces;     -   the discharge means comprise a discharge tunnel arranged in the         bottom and/or the cover, said tunnel connecting a containment         space and the outside of the enclosure;     -   the seal is an O-ring received in grooves provided respectively         on the two opposite front faces.

A further object of the present invention is a method for the use of an exchanger such as that above, wherein the first and second fluids are circulated in the first and second channels, so as to enable the heat exchange thereof, and the circulation of at least one fluid is shut down if the presence of said fluid is detected in at least one annular containment space.

According to further features of the method according to the invention:

-   -   at least one inner seal is replaced if the presence of the first         fluid is detected in at least one annular containment space;     -   the outer seal is replaced if the presence of the second fluid         is detected in at least one annular containment space.

A further object of the present invention is a heat exchange block comprising a body, first so-called longitudinal channels, formed in this body along a longitudinal direction of the block, which open onto two opposite front faces of the body, second so-called transverse channels, formed in this body along a transverse direction of the block, which open onto two opposite transverse faces of the body,

said block being characterized in that it further comprises, on each front face,

at least one so-called radially inner peripheral seat which extends radially outside the area of the openings of the longitudinal channels, this seat being suitable for receiving a first seal,

a so-called radially outer peripheral seat suitable for receiving a second seal, this outer peripheral seat defining with the inner peripheral seat an annular intermediate section

and in that at least one discharge conduit connects the opposite front faces and opens onto the two opposite annular sections.

The invention makes it possible to achieve the objectives mentioned above. A heat exchanger, of the type targeted by the invention, defines a certain number of interfaces, between the opposite front faces of the constituent elements thereof. Consequently, a first interface between the cover and the block adjacent thereto, and an opposite interface between the bottom and the adjacent block are observed, along with possible additional interfaces between each pair of contiguous blocks.

The invention relates to two main types of heat exchangers. According to a first embodiment, only the first channels, intended for the circulation of a first fluid, referred to as process fluid, are longitudinal and open onto the front faces of each block. On the other hand, the second channels, intended for the circulation of the heat transfer fluid, are transverse and open onto the lateral faces of each block. In this case, the inner seal(s) surround(s) only the opening of the first channels, at the level of the front faces. A single inner seal is typically provided, forming an annular containment space with the outer seal.

According to an alternative embodiment, both the first and the second channels are longitudinal and open onto the front faces of each block. In this case, at least two inner seals are provided, of which one surrounds the opening of the first channels and the other the opening of the second channels. A greater number of inner seals may be provided, according to the arrangement of the various channels. In the typical case of a succession of alternating rows between the first and the second channels, a number of inner seals corresponding to the number of rows are provided.

The invention ensures sealing between the two fluids placed in heat exchange, firstly by means of the inner seal(s). In the event of malfunction of this/these inner seal(s), the potential leak of fluid is contained due to the presence of the outer seal. This double degree of safety is provided on at least one of the interfaces listed above, in particular on all the interfaces between each pair of contiguous blocks, preferably on all the interfaces listed above. This provides enhanced sealing and safety, in particular compared with solutions involving a single seal between these two flows.

In this regard, it shall be pointed out that, in the exchanger according to FR 1 421 491 and FR 1 465 780, a single seal is observed extending outside the area of the openings. In other words, all the pairs of seals of this exchanger define spaces where the normal fluid flow channels open. Consequently, this exchanger does not define a space for containing a potential leak.

The invention further makes it possible to notify the operator substantially immediately, in the event of a malfunction of one of the seals. According to the type of fluid, contained in the annular space and then discharged outside the exchanger, the operator knows which of the two seals is not working. The operator can then carry out a full replacement of this defective seal, before resuming use of the installation.

It shall be noted that the invention makes it possible to do away substantially with any risk of contact between the two fluids. Indeed, such contact only occurs in the case, which is highly improbable in practice, where the two seals change simultaneously from an operational state to a defective state. In the most common case, only one of these seals stops working while the other remains operational. The operator is notified thereof without delay, shuts off the flow of the fluids and replaces the defective seal.

Consequently, the exchanger according to the invention is very particularly suitable for heat exchange between two high-criticality fluids. Mention shall be made for example of the case where one of the two fluids has a high purity, such that it does not accept any contamination, or the case where the mixture between these fluids can give rise to an explosion or an emission of noxious gas.

Finally, the blocks belonging to the exchanger according to the invention have a small number of additional mechanical members, compared with conventional blocks according to the prior art. Moreover, these mechanical members are provided at a distance of the fluid flow channels. Consequently, the manufacture of these blocks does not give rise to a significant increase in rupture risks. Furthermore, in operation, these blocks exhibit a satisfactory robustness and service life.

DESCRIPTION OF THE FIGURES

The invention will be described hereinafter, with reference to the appended drawings, given by way of non-limiting example, wherein:

FIG. 1 is a longitudinal sectional view, illustrating a heat exchanger according to the invention;

FIG. 2 is a perspective view with cutaways, illustrating a block belonging to the exchanger in FIG. 1;

FIG. 3 is a longitudinal sectional view, similar to FIG. 1, illustrating in more detail a longitudinal end of the heat exchanger according to the invention; and

FIGS. 4 to 6 are longitudinal sectional views on a much larger scale, illustrating the junction area between two blocks, respectively in a sealing configuration and in two leak configurations of one or the other of the two fluids circulating in this exchanger.

FIG. 7 is a top view, illustrating a heat exchange block belonging to a heat exchanger according to an alternative embodiment of the invention.

FIGS. 8 and 9 are top views, similar to FIG. 7, illustrating two leak configurations of one or the other of the two fluids circulating in the exchanger in this FIG. 7.

DETAILED DESCRIPTION OF THE INVENTION

The following reference signs are used in the figures:

1-3 Heat exchange blocks  6 Casing  4 Bottom  61 Edge of 6  5 Cover  62 Chamber of 6 112  Interface between 63, 34 Tubes of 6 1 and 2 114  Interface between J1, J2 Seals between 1 1 and 4 and 2 123  Interface between I1, I2 Functional gaps 2 and 3 135  Interface between J′1, J′2 Seals between 1 3 and 5 and 4 L  Main axis of exchanger  E, E′ Containment spaces L1 Main axis of block 1  80 Detection member 10 Longitudinal  82 Alarm channels of 1 11, 11′ Front faces of 1 201 Heat exchange block 12 Transverse channels of 1 210 1st channels of 201 13, 13′ Transverse faces of 1 211 Front face of 1 14 Area of openings of 10 212 2nd channels of 201 15, 15′ Inner grooves of 10 R1-R3 Rows of channels 210 16, 16′ Outer grooves of 10 R′1, R′2 Rows of channels 212 17, 17′ Annular sections DR1-DR3 Area of openings of R1-R3 18, 28, 38 Conduits DR′1-DR′2 Area of openings of R′1-R′2 41 Opening of 4 JR1-JR3 Seals of R1-R3 42 Plate of 4 JR′1-JR′2 Seals of R′1-R′2 43 Tunnel 217 Intermediate section 44 Opening of 43 218 Conduit 51 Opening of 5 E201 Containment space

As illustrated particularly in FIG. 1, the heat exchanger according to a first embodiment of the invention essentially comprises a plurality of heat exchange blocks 1 to 3, a bottom 4, a cover 5, as well as a peripheral casing 6. In the example, three blocks stacked on top of one another have been represented, it being understood that a different number of blocks may be envisaged. The interfaces between the opposite front faces of these constituent elements are referenced, from top to bottom, 135, 123, 112 and 114.

Hereinafter, the structure of the block 1 will be described more specifically, it being understood that the blocks 2 and 3 have a similar structure. The mechanical elements of these blocks 2 and 3 equivalent to those of the block 1 are assigned the same reference numbers, the prefix “1” being replaced respectively by “2” or “3”. These different blocks are made of any suitable material, known from the prior art, such as for example graphite. As shown particularly by FIG. 2, the block 1 has a cylindrical shape, with a circular cross-section. Alternatively, it may be of a different shape, particularly parallelepipedic, in particular cubic. L1 refers to the main or longitudinal axis thereof, which is parallel with the main axis L of the exchanger. In a manner known per se, this block 1 is hollowed with different channels, with a view to the flow of two fluids intended to be placed in mutual heat exchange.

Firstly, a first series of channels 10 parallel with the axis L1, referred to as longitudinal channels, are observed, which open onto the opposite front faces 11 and 11′ of the block. Moreover, a second series of transverse channels 12, extending obliquely, particularly perpendicular to the axis L1, open onto the opposite transverse faces 13 and 13′ of the block. In operation, two fluids, circulating respectively in the first and second series of channels, are placed in heat exchange. These channels are distant from one another, that is to say they do not open into one another.

On the front face 11, the so-called opening area 14 of the longitudinal channels has been illustrated with dotted lines. This area 14, circular in shape, connects the outer edge of the peripheral longitudinal channels. A similar opening area, not shown, is associated with the other front face 11′.

Each front face is hollowed with two concentric grooves, of which one 15 or 15′ is referred to as radially inner and the other 16 or 16′ radially outer. Each inner groove 15 and 15′ is formed outside the opening area, that is to say the inner edge of this groove is distant from the opening of the peripheral channels.

The grooves 15, 15′, 16 and 16′ are suitable for forming the seat of a sealing member, for example of the O-ring type. In the example illustrated, they have a cross-section in the shape of an arc of a circle. Nevertheless, they may adopt any other profile, suitable for receiving the abovementioned sealing member. The two annular intermediate sections, defined by the opposite edges of the inner and outer grooves, are referenced 17 and 17′.

The block 1 is hollowed with a conduit 18, extending globally along the direction L1, which opens onto the front faces 11 and 11′ by connecting the two intermediate sections 17 and 17′. It may be envisaged to provide a plurality of conduits, similar to 18, preferably regularly angularly distributed. Non-restrictively, the cross-section of each conduit is between 0.1 and 50 mm (millimeters).

In terms of manufacturing process, the channels 10 and 20 are hollowed in a routine manner. The conduit 18 is perforated according to a similar process, equally well before or after producing the channels. Finally, the various grooves 15, 15′, 16 or 16′ are formed by any suitable means, here again equally well before or after producing the channels.

Once again with reference to FIG. 1, the bottom 4 is hollowed with an opening 41 intended for the inlet of a first fluid into the channels 10. This inlet is connected with a source of this fluid, which is situated upstream and is not illustrated. Similarly, the cover 5 is hollowed with an opening 51 intended for the outlet of the first fluid outside the channels 10. This outlet is connected with a recovery tank, which is situated downstream and is not illustrated.

The stack of blocks 1 to 3 is surrounded by means of a casing 6 defining a receiving enclosure, with the bottom and the cover. Conventionally, this casing has an edge 61, suitable for securing same onto a plate 42, belonging to the bottom (see FIG. 3). Similarly, it is provided with means suitable for securing same onto the cover.

This casing defines, with the opposite walls of the blocks, a peripheral chamber 62 intended for the circulation of a second fluid, intended to be placed in heat exchange with the first fluid in the blocks 1 to 3. For this purpose, the casing is equipped with respective inlet 63 and outlet 64 tubes of this second fluid, connected with a source and a recovery tank.

The various mechanical elements, listed in the last three paragraphs, are of the type known per se. Consequently, they will not be described in more detail hereinafter.

FIG. 4 illustrates the stack between the blocks 1 and 2. Two O-rings J1 and J2 are received in the respective grooves 15 and 25′, as well as 16 and 26′. The front faces 11 and 21′ of the blocks are arranged facing, providing functional gaps I1 and I2, the thickness whereof has been enlarged in the drawing for the purposes of clarity.

Furthermore, a so-called containment interposed space E is formed between the opposite walls belonging to the sections 17 and 27′, as well as to the seals J1 and J2. This space is annular, in that it extends over the entire periphery of the interface 112. The conduits 18 and 28, hollowed in the blocks 1 and 2, open into this space E.

As illustrated in FIG. 3, the stack between the block 1 and the bottom 4 is similar to the stack described above between the two blocks 1 and 2. Two O-rings J′1 and J′2 are observed, inserted between the opposite front faces of this block 1 and of this bottom 4. These seals and these front faces define an annular containment space E′, similar to E above.

The bottom 4 is further hollowed with a discharge tunnel 43, connecting the annular space E′ and the outside of the enclosure. The opening of this tunnel on the outer front face of the cover is referenced 44. The walls of this opening receive the first end of a pipe 70, of any suitable type, wherein the other end engages with a detection member 80. The latter is suitable for emitting a signal to the operator via an alarm 82, when it detects the arrival of one or the other of the two fluids circulating in the different blocks 1 to 3. This signal may be of any suitable type, in particular audio, visual or electronic.

A similar stack is observed, firstly between the other blocks 2 and 3 and, secondly, between the block 3 and the cover 5. At each interface respectively 123 and 135, two O-rings are inserted between the opposite faces of these mechanical elements, defining two further containment spaces. Furthermore, the block 3 is hollowed with a conduit similar to that 18 formed in the block 1. On the other hand, the cover is not equipped with a tunnel, such as that 43 of the bottom.

The use of the heat exchanger, described above, will now be explained hereinafter.

The first fluid placed in heat exchange is admitted via the inlet opening 41, flows successively into the channels 10, 20 and then 30, before being discharged via the outlet opening 51. The second fluid is admitted via the inlet tube 63, flows into the channels 12, 22 and 32, before being discharged via the outlet tube 64. These flows are represented by arrows with respectively dotted and dot and dash lines, in FIG. 1.

FIG. 4 illustrates more particularly the flow of the fluids between the blocks 1 and 2, it being understood that this flow is similar between the other blocks 2 and 3, between the block 1 and the bottom, as well as between the block 3 and the cover. When these fluids infiltrate the respective gaps I1 and I2, they come into contact with the seals J1 and J2. In normal operation illustrated in this FIG. 4, the seals J1 and J2 are operational such that they prevent the flow of the fluids toward the annular space and that there is no mixing between these fluids. No fluid flows into the pipe 70, represented schematically in this FIG. 4, while the detector 80 and the alarm 82 are inactive, such that they are represented by dotted lines.

On the other hand, let us now suppose that the inner seal J1 is defective, as illustrated in FIG. 5. A leak of the first fluid therefore occurs, from the gap I1 toward the safety space E. It shall be noted that this first fluid cannot be placed in contact with the second fluid present in the gap I2, due to the presence of the seal J2 which remains operational. This first fluid is then routed along the conduit 18, and then the tunnel 43.

The first fluid is then discharged from the enclosure, via the pipe 70, toward the detection member 80. The latter then activates the alarm 82, which indicates to the operator that the operation of the installation needs to be shut down. The operator is further informed of the nature of the fluid discharged in this way, so as to be able to carry out a full replacement of the first seal J1.

Let us now suppose that the outer seal J2 is defective, as shown in FIG. 6, a second leak of the second fluid occurs, from the gap I2 toward the safety space E. It shall be noted that this second fluid cannot be placed in contact with the first fluid present in the gap I1, due to the presence of the seal J1 which remains operational.

This second fluid is then routed, via the conduit 18, the tunnel 43 and then the pipe 70, toward the detection member. As in the previous case, the operator is notified of the malfunction, in order to shut down the use of the installation and carry out the replacement of this second seal J2.

If the leak of one or the other fluid occurs at the interface between the upper block 3 and the cover 5, the fluid is discharged successively along the conduits 38, 28 and 18, before being discharged via the tunnel 43. If this leak occurs at the interface between the two blocks 2 and 3, the fluid is discharged successively along the conduits 28 and 18, before being discharged via the tunnel 43. Finally, if this leak occurs at the interface between the low block 1 and the bottom 4, the fluid is discharged directly via the tunnel 43.

The conduits 18, 28 and 38, as well as the tunnel 43, form discharge means, suitable for routing a potential leak of fluid outside the enclosure. These conduits and this tunnel do not open into the fluid flow channels, whether those oriented longitudinally or those oriented transversely.

FIG. 7 illustrates a heat exchange block 201 belonging to a heat exchanger according to an alternative embodiment of the invention. In this figure, the mechanical elements equivalent to those in the preceding figures are assigned the same reference numbers, increased by 200, therein.

The block 201 in FIG. 7 differs from that in FIGS. 1 to 6, firstly in that it is rectangular in shape, but also in that the two series of channels are parallel and open onto the front faces of each block, of which only one 211 is referenced in this figure. Therefore, firstly, the first series of channels 210, similar to those 10 in the preceding figures, is observed. The second series is also formed from longitudinal channels 212, as opposed to the transverse channels 12 in the preceding figures.

These various channels 210 and 212 are substantially parallel, that is to say they do not open into one another. As in the embodiment in the preceding figures, two fluids, circulating respectively in the first and second series of channels, are placed in heat exchange. These two fluids are of the same type, as those described above.

More specifically, the channels are formed by parallel rows, arranged in alternation in a top view. As such, three rows R1 to R3 of first channels 210 are observed, as well as two rows R′1 and R′2 of second channels 212. In FIG. 7, the various areas of openings of the longitudinal channels, that is DR1 to DR3 for the rows of the first series and DR′1, DR′2 for the rows of the second series have been illustrated with dotted lines. Each area, of a rectangular shape, extends along the periphery of a respective row of channels.

The front face 211 is hollowed with so-called inner rectangular grooves, each of which extends outside a corresponding opening area. The different inner grooves receive respective sealing members, JR1 to JR3, as well as JR′1 and JR′2, which are for example equivalent to that J1 of the first embodiment. This front face 211 is further hollowed with a so-called outer peripheral rectangular groove, which surrounds the different inner grooves mentioned above. This outer groove receives a sealing member JP, which is for example equivalent to that J2 of the first embodiment.

The intermediate section, defined by the opposite edges of the inner and outer grooves described above, is referenced 217. An intermediate section, not shown, is defined similarly on the other front face of the block 201. This block is further hollowed with a plurality of conduits 218, generally parallel with the channels 210 and 212, which open onto the front faces connecting the two intermediate sections defined above. In the example illustrated, four of these conduits have been provided, placed in the vicinity of the corners of the block, it being understood that a different number of conduits and/or a different arrangement of these conduits may be envisaged.

When the block 201 is stacked on a similar block not shown, these contiguous blocks define a containment space E201, similar to that E in the preceding figures. This space is defined by the opposite faces belonging to the section 217 and to the second not shown of the contiguous block, as well as by the seals JP, JR1 to JR3, as well as JR′1 and JR′2. As in the first embodiment, further containment spaces are advantageously formed by the opposite walls of the other contiguous blocks, by the opposite walls of the bottom and of the block contiguous thereto, as well as by the opposite walls of the cover and of the block contiguous thereto.

In normal operation illustrated in FIG. 7, the inner seals are operational, such that they prevent the flow of the fluids toward the containment space and that there is no mixing between these fluids.

Let us suppose that one of the seals JR1 to JR3, for example JR1, is defective, a leak of the first fluid therefore occurs toward the safety space E201. It shall be noted that this first fluid cannot be placed in contact with the second fluid, due to the presence of the seals JR′1 and JR′2 which remain operational. This first fluid is then routed along the conduits 218, along the dotted lines illustrated in FIG. 8. It then flows into a tunnel not shown similar to 43, before being discharged outside the enclosure, as in the first embodiment.

Let us now suppose that one of the seals JR′1 or JR′2, for example JR′1, is defective, a leak of the second fluid occurs toward the safety space E201. It shall be noted that this second fluid cannot be placed in contact with the first fluid, due to the presence of the seals JR1 to JR3 which remain operational. This second fluid is then routed along the conduits 218, along the dot and dash lines illustrated in FIG. 9. It then flows into the tunnel not shown mentioned in the previous paragraph, before being discharged outside the enclosure.

The invention is not limited to the example described and represented. In particular, O-rings have been illustrated, as respectively inner and outer sealing members. Nevertheless, it may be envisaged to replace these O-rings by any other suitable seals, for example a multiple seal. 

1. Heat exchanger comprising an enclosure having a bottom (5), a cover (4) and a peripheral casing (6), at least one block (1-3; 201) arranged between the bottom and the cover, each block comprising a body, first so-called longitudinal channels (10; 210), formed in this body along a longitudinal direction (L1) of the block, which open onto two opposite front faces (11, 11′; 211) of the body second channels (12; 212), formed in this body along a second direction, which is: either a transverse direction, these second channels then being transverse channels, which open onto two opposite transverse faces (13, 13′) of the body, or said longitudinal direction, these second channels then being longitudinal channels (212) also opening onto said opposite front faces (211) of the body, the exchanger further comprising first inlet means (41) of a first fluid into the first channels second inlet means (63) of the second fluid into the second channels first outlet means (51) of the first fluid from the first channels second outlet means (64) of the second fluid from the second channels sealing means between the first and second fluids, said exchanger being characterized in that the sealing means comprise, on at least one interface of the interfaces (112, 114, 123, 135) between two opposite front faces belonging: to the cover and to the block adjacent thereto to the bottom and to the block adjacent thereto optionally to two contiguous blocks at least one so-called radially inner peripheral seal (J1, J′1; JR1, JR′1, JR2, JR′2, JR3), each inner seal extending radially outside the area (14; DR1, DR′1, DR2, DR′2, DR3) of the openings of at least a portion of the longitudinal channels, and a so-called radially outer peripheral seal (J2, J′2) defining, with the inner peripheral seal(s) and the opposite front faces, a space (E, E′; E201) for containing a possible leak of one or the other fluid.
 2. Heat exchanger according to claim 1, characterized in that the second channels (12) are transverse and a single radially inner seal (J1, J′1) is provided, extending radially outside the area of the openings of the longitudinal channels, the containment space (E, E′) being annular in shape.
 3. Heat exchanger according to claim 1, characterized in that the second channels (212) are also longitudinal and at least one first radially inner seal (JR1, JR2, JR3) is provided, each first inner seal extending outside the area (DR1, DR2, DR3) of the openings of at least a portion of the first longitudinal channels, as well at least one second radially inner seal (JR′1, JR′2), each second inner seal extending outside the area (DR′1, DR′2) of the openings of at least a portion of the second longitudinal channels.
 4. Heat exchanger according to claim 3, characterized in that the first (210) and second (212) longitudinal channels are arranged in a succession of alternating rows (R1, R′1, R2, R′2, R3), the area (DR1, DR′1, DR2, DR′2, DR3) of the openings of each row being surrounded by a respective radially inner seal (JR1, JR′1, JR2, JR′2, JR3).
 5. Heat exchanger according to claim 1, characterized in that it comprises at least two blocks (1-3) stacked on top of one another along a longitudinal direction (L) of the exchanger, between the bottom (4) and the cover (5).
 6. Heat exchanger according to claim 5, characterized in that the sealing means comprise said at least one inner peripheral seal (J1) and said outer peripheral seal (J2), at all of the interfaces (112, 123) between two contiguous blocks.
 7. Heat exchanger according to claim 1, characterized in that the sealing means comprise said at least one inner peripheral seal (J1, J′1) and said outer peripheral seal (J2, J′2), at all of said interfaces (112, 114, 123, 135).
 8. Heat exchanger according to claim 1, characterized in that it further comprises detection means (80), suitable for detecting the presence of at least one of the first and the second fluid, inside at least one annular containment space (E, E′).
 9. Heat exchanger according to claim 8, characterized in that it further comprises an alarm (82) suitable for being activated by detection means (80).
 10. Heat exchanger according to claim 1, characterized in that it further comprises discharge means (18, 28, 38, 43), suitable for discharging outside the enclosure (4, 5, 6) said potential leak of one or the other fluid, contained in at least one annular space.
 11. Heat exchanger according to claim 10, characterized in that the discharge means (18, 28, 38, 43) are placed in communication by the fluid with the detection means (80).
 12. Heat exchanger according to claim 11, characterized in that the detection means (80) are at a distance from the enclosure (4, 5, 6) and a connection pipe (70), suitable for connecting these detection means and the opening (44) of the discharge means is provided.
 13. Heat exchanger according to claim 10, characterized in that the discharge means comprise at least one discharge conduit (18, 28, 38), each discharge conduit being provided in a respective block and connecting two adjacent containment spaces (E, E′).
 14. Heat exchanger according to claim 10, characterized in that the discharge means comprise a discharge tunnel (43), arranged in the bottom (4) and/or the cover, said tunnel connecting a containment space (E) and the outside of the enclosure.
 15. Method for the use of an exchanger according to claim 8, wherein the first and second fluids are circulated in the first and second channels, so as to enable the heat exchange thereof, and the circulation of at least one fluid is discontinued if the presence of said fluid is detected in at least one annular containment space.
 16. Method according to claim 15, wherein at least one inner seal is replaced if the presence of the first fluid is detected in at least one annular containment space.
 17. Method according to claim 16, wherein the outer seal is replaced if the presence of the second fluid is detected in at least one annular containment space.
 18. Heat exchange block (1; 201) comprising a body, first so-called longitudinal channels (10; 210), formed in this body along a longitudinal direction (L1) of the block, which open onto two opposite front faces (11, 11′; 211) of the body, second channels (12; 212), formed in this body along a second direction, which is: either a transverse direction, these second channels then being transverse channels, which open onto two opposite transverse faces (13, 13′) of the body, or said longitudinal direction, these second channels then being longitudinal channels (212) also opening onto said opposite front faces (211) of the body, said block being characterized in that it further comprises, on each front face, at least one so-called radially inner peripheral seat (15, 15′), each inner seat extending radially outside the area of the openings of at least one part of the longitudinal channels, the or each inner seat being suitable for receiving a respective inner seal, a so-called radially outer peripheral seat (16, 16′), suitable for receiving an outer seal, this outer peripheral seat defining with the inner peripheral seat an annular intermediate section (17, 17′; 217) and in that at least one discharge conduit (18) connects the opposite front faces and opens onto the two opposite sections (17, 17′). 